The Belzer LI-400 preservation unit will be used to study a major unanswered problem in preservation. Intrarenal distribution of perfusate flow using radioactive microspheres will be evaluated as a means for determining effectiveness of preservation and for prediction of post-transplant organ function. If the importance of alterations of intrarenal distribution of flow can be proven using the radioactive microsphere method, the technique designed by Powers will be used to determine distribution of intrarenal flow by measurement of changes in temperature differences between two closely spaced thermistor probes. This method would permit determination of intrarenal flow patterns during perfusion and could therefore be employed as another tool to evaluate kidneys on perfusion for their suitability for transplantation. Emphasis will be placed upon the importance of the effects of damage by warm ischemia on intrarenal distribution, and a variety of pharmacological agents will be tested to determine if intrarenal flow can be altered favorably during perfusion and if such will result in improvement of function after renal implantation.